#include <stdio.h>
#include <math.h>

int main(){ 
    float a,b,c;
    float s;
    float result;
    printf("I want to get the AREA of triangle!\n");
    printf("Please input 3 float type NUM! (like: float,float,float)\n");
    scanf("%f,%f,%f",&a,&b,&c);

    s = (a+b+c)/2.;
    result = sqrt(s*(s-a)*(s-b)*(s-c));
    printf("Result is %.2f",result);

    return 0;
}
